As an increasing number of applications and services are being made available over networks such as the Internet, an increasing number of content, application, and/or service providers are turning to technologies such as cloud computing. Cloud computing, in general, is an approach to providing access to electronic resources through services, such as Web services, where the hardware and/or software used to support those services is dynamically scalable to meet the needs of the services at any given time. A user or customer typically will rent, lease, or otherwise pay for access to resources through the cloud, and thus does not have to purchase and maintain the hardware and/or software needed.
Many cloud computing providers utilize virtualization to allow multiple users to share the underlying hardware and/or software resources. Virtualization can allow computing servers, storage devices or other resources to be partitioned into multiple isolated instances (e.g., virtual machines) that are each owned by a particular user. These virtual machines are often hosted using a hypervisor running on a host computing device. In this context, it is sometimes desirable to migrate a virtual machine from one host computing device to a different host computing device.